The efficacy of molnupiravir (MLN) on Omicron sublineages is limited. We investigated the effectiveness of MLN in older adults diagnosed with Omicron BA.2.Data of elderly COVID-19 patients (over 60 years) admitted to Chinghai Hospital (Shanghai, China) from 26 March to 31 May 2022 were reviewed. Study outcomes were a composite of undetectable viral load (VL) and disease progression [all-cause mortality, initiation of oxygen supply through high-flow device or invasive mechanical ventilation (IMV), or intensive care unit (ICU) admission] and their individual outcomes.A total of 42 elderly patients were enrolled: 26 of them received MLN, 17 (40.5%) were males, the median age was 84 years, and 12 were fully vaccinated (31.0%). Among these elderly COVID-19 patients, five (11.90%) experienced obvious dyspnea or were transferred to ICU [three MLN users (11.5%) versus two non-MLN users (12.5%)]. Compared with no MLN use, MLN use was associated with rapid undetectable VL. At day 10, MLN users achieved significantly greater undetectable VL than non-MLN users. Adjusted analysis showed that elderly patients who received MLN were 7.584 times more likely to achieve undetectable VL at day 10 than non-MLN users. Overall, elderly patients experienced a median hospital stay of 13 days. Compared with patients receiving standard care (SC), the median hospital stay of MLN users was reduced by 2.5 days.Early initiation of MLN in elderly COVID-19 was associated with fast undetectable VL and short hospital stay.